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Developing for foldable devices: What you need to know
July 29, 2025
The age of thefoldable deviceis upon us! Or at least it will be very soon,pending a slight delay.
Either way, a lot of industry analysts are of the opinion that folding smartphones are the future. That means the apps of the future also need to be foldable. Consumers are clamouring at the bit to get a taste of this new hardware direction. But as for us developers? It’s just one more form factor to target — the Android landscape is becoming even more fragmented! Yay!
One thing that struck me as unusual watchinghands-on videos of the Galaxy Fold, was the fact thatmost appsappeared to support it already. Reviewers raved about “app continuity,” and how most apps would jump from the front display to the large central display seamlessly.
Apps thatdon’tsupport the feature will open up in the middle of the display without scaling and will need to be relaunched. This is pretty janky effect, and seeing as most developers are playing ball, we really want to be on the right side of history here.
Getting started – emulating foldable devices
The first thing you need to do is download yourself a copy ofAndroid Studio 3.5 Canary 13and create a new virtual device withAndroid Q Betaand a folding form factor. This will let you test your app to see how it handles being folded in half. Once you have Android Studio, you can get everything you need through the AVD Manager as normal.
Be warned that the foldable emulator isdefinitelya beta product, and you’ll certainly run into a few bugs. I’ve been trying to load it as I write this article and it’s currently crashing for the third time. That said, once it’s up and running, it’s a useful way to quickly test everything is scaling as it should.
There are other options too. You can head over toSamsung’s Remote Test Laband try to remotely run a Galaxy Fold. That means controlling anactualdevice somewhere. I quite enjoy the fact that it requests you don’t use it to install and playFortnite! This is not perfect — it’s pretty slow — but it’s also interesting for anyone keen to have a go with a Fold (like yours truly).
Finally, you also have the option to try an emulator provided directly from Samsung. What’s cool about this one is that it comes in APK format and therefore actually runsonyour Android device. you’re able to get the APK and find instructions for using ithere.
To be honest though, you can test a lot of what we’re about to talk about using good-old multi window. To try multi-resume right now (explained below in a moment), trythis trick I wrote about a while back using Samsung MultiStar.
Supporting app continuity
Once that’s up and running, you’re ready to start making the essential changes. To support screen continuity, you need to ensure that your app supportsruntime configuration change. This is something developers should be consideringanyway, as it also relates to using multi-window mode.
(I’ve been playing around with my old Axon M — which is still onAndroid 7.1— and I’m surprised at how many apps already adapt seamlessly when you open the thing up.)
The way we do this is throughonSaveInstanceState()and persistent storage. In other words, make sure you are saving your layout and any crucial data duringonPause()and then retrieving as necessary. You can also useViewModelin order to retain data during configuration changes.
Of course, the layout of your app itself also needs to be capable of scaling seamlessly. This is partly the result of goodUI design, and partly a matter of usingConstraintLayoutso that your views are all positioned relative to the edges of the display. Avoid hard coding your layout sizes, and instead rely on “wrap_content,” and “match_parent.”
But avoid the temptation to simply stretch everything to fit. Otherwise, what’s the point?
Users really value a layout that takes full advantage of the massive screen real-estate that they’re paying ~$2,000 to enjoy. Think about the way Gmail adapts to show two columns on tablet — You can achieve the same thing by usingalternate layout resources.
It’s a bit of extra work on your part, but it can significantly improve the experience for the end user. If you improve the experience, users are more likely to open your app more often — meaning you’ll earn more money!
Multi-resume
Speaking of the app life-cycle, it’s also worth noting the changes Google has made toonResume(). Specifically, more than one app will now be able to be in a resumed state, meaning that you won’t need to worry quite so much about handling your app being paused-but-visible. That means many of Google’s recommendations in this department are no longer relevant, but it’s still worth giving theMulti-Window Support guidelinesa read if you haven’t already.
To support this though, you’ll need to add the tag:android.allow_multiple_resumed_activitiesto your manifest. Then you’ll need to spend some time thinking about how this might change the way that users interact with your apps. Deciding when to pause media or when to update feeds will be the difference between a seamless or flawed experience.
You’ll also need to use the resizeableActivity attribute:android:resizeableActivity, which has undergone some changes in Android Q.
Closing comments
As you can see then, there’s nothing too new here — and that’s likely why so many apps already supported app continuity by default. This has been handled smartly by Google, meaning that for once there isn’t too much work for us to do. Rather, it’s a matter of playing catch-up to ensure an app is already well optimized for the ever-expanding range of form factors that can run it, testing it with the relevant emulators and tools, and being ever-smarter about UI design.
The good news is that larger screen sizes should equate to better user engagement. Get your UX right, and this could translate to a lot more screen time for your projects!
Be sure to check back here from time to time. We’ll be adding more instructions and tips as we learn more.
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